Fig. 123. Fragrant shield fern (Aspid- 

 ium fragrans), showing general 

 habit, and to the left (a) the under 

 surface of a leaflet bearing sori 

 covered by shield-like indusia.— 

 After Marion Satterlee. 



Fig. 124. The bladder fern ( Cystopteris bulb- 

 ifera), showing general habit, and to the 

 right (a) the under surface of a leaflet, 

 showing the dichotomous venation, and 

 five sori protected by pouch-like indusia. 

 —After Marion Satterlee. 



